Differential feeding mechanism for sewing machines



Oct. 25, 1932. F Z R ET AL 1,884,489

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES Filed Nov. 5, 1930 2Sheets-Sheet l Q\\ l @r Q g lg 0 NW \W A: I I x\ I I i :|l L k i 0 r 1 li gg g $0 R s El a I Q gw wnkozs Get. 25, 1932. ZElER ET AL 1,884,489

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES Filed Nov. 5, 1950 2Sheets-Sheet 2 mnnnnnnggg Patented Oct. 25, 1932 PATENT OFFICE IBEDERICKI. ZEIER AND CLARENCE C. SMITH, OF CHICAGO, ILLINOIS, ASSIGNORS TO UNIONSPECIAL MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 01'ILLINOIS DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES Applicationfiled November 5, 1980. Serial Ho. 498,848.

The invention relates to new and useful improvements in a sewing machineand more particularly to a feeding mechanism for. glving a. differentialmovement to the feed dogs.

An object of the invention is to provide a differential feedingmechanism wherein the feed bar carrying the auxiliary feed dog 1smounted for reciprocation 1n supportmg bearings spaced from each otherand 1s moved back and forth therein by a connection attached to the feedbar between said supporting bearings.

A further object of the invention is to provide a feeding mechanism ofthe above type r wherein the feed bar supporting bearings are in theform of sleeves and the feed bar is circular in cross section andwherein means 1ndependent of the bearings is provided for holding saidfeed bar to a right line back and forth movement.

A further object of the inventlon 1s to provide a feeding mechanism ofthe above type wherein the feed dog is secured to the feed bar at apoint adjacent one of the supporting bearings for the feed bar andwherein the means which holds the feed bar to a right ine movement isdisposed at a distance therefrom so that the wear of the parts in eitherinstance has little effect on the movements of the feed dog back andforth.

A still further object of the invention is to provide a feedingmechanism of the above type wherein the feed bar is made hollow so as toreduce the weight thereof to a minimum.

These and other objects will in part be obvious and will in part behereinafter more fully disclosed.

In the drawings which show by way of illustration one embodiment of theinvention:

Fig. 1 is a view partly in section and partly in plan showing a portionof a sewing ma chine having the improvements applied thereto.

Fig. 2 is an enlarged view partly in section and partly in sideelevation showing the improved feeding mechanism.

Fig. 3 is a view of the same from the rear of the machine and showing aportion of the work support.

F Fig. 4 is a sectional view on the line 4, 4, of

The invention is directed to a feeding mechanism for sewing machineswhich is provided with a main feed dog operating on the material in rearof the needles and an auxiliary feed dog operating on the material inadvance of the needles. This auxiliary feed dog is mounted on a feed barwhich is in the form of a sleeve circular in cross section. The feed baris made in sleeve form so as to reduce its weight and still afford asubstantial bearing surface for the feed bar. The feed bar is mountedfor reciprocation in two sleeve bearings formed integral with the mainfeed bar. There is a sleeve mounted on this auxiliary feed bar which islocated between the bearings and a link is connected to the sleeve formoving the feed bar back and forth. The sleeve is provided with aprojecting arm, the outer end of which slides freely back and forthbetween two spaced guide bars and this holds the feed bar so that thefeed dog will have a movement in a vertical plane.

Referring more in detail to the drawings, the invention is shown asapplied to a sewing machine which includes a supporting bed 1 providedwith the usual standard 2 carrying the overhanging arm and the needle.Mounted in this bed is a main actuating shaft 3. The parts of thestitching mechanism and thread controllers, shown more or lessdiagrammatically in Fig. 1 of the drawings, have not been described asthey form no part of the present invention.

The present invention has to do with a feeding mechanism which includesa main feed dog 5 and an auxiliary feed dog 6. The main feed dog 5 iscarried by a feed bar 7 which extends rearwardly and is provided with asleeve 8 freely connected to a rod 9 carried by the feed rocker 10 andsecured thereto by screws 10', 10. The feed rocker carries a sleeve 9'which is integral therewith. A link 11 is provided with a collar 11which surrounds the sleeve 9' and is secured thereto b screws 11", 11".This link is connected to tile crank 12 carried by the main shaft 3.Thus it is that the feed rocker is oscillated and the feed bar 7movedback and forth.

The feed bar carries a depending arm 13 which extends beneath the shaft3. An eccentric strap 14 cooperates with an eccentric 15 on the mainshaft and is pivoted at 16 to the arm 13. As the shaft oscillates theeccentric stra will raise and lower the forward end of the feed bar andgive to the feed dog its rising and falling movements. The auxiliaryfeed dog 6 is carried by the feed bar 17. This feed bar 17 is circularin cross section and is hollow as indicated at 18 in Fi 4 of thedrawings. This makes a very lig t feed bar which has sufficient surfacein order to provide ample bearing support for the auxiliary feed bar.The feed bar 7 1s rovided with two sleeve bearings 19 and 20. l'hebearing 20 is located very close to the head 21 on the forward end ofthe auxiliary feed bar to which the auxiliary feed dog 6 is attached.Said auxiliary feed dog is attached to the head 21 by a screw 22 and aribbed connection so that it may be readlly adjusted vertically and heldfrom tilting or angular movement on the auxiliary feed bar. Located onthis auxiliary feed bar 17 intermediate the bearings 19 and 20 is asleeve 23 which is secured to the feed bar by means of set screws 24.This sleeve carries a laterally projecting stud 25. The feed rocker 10is provided with an upstanding bracket arm 26 provided with a slot 27. Astud 28 is adjustable in the slot and clamped in 'an adjusted positionby a nut 29. This stud projects to the inner side of the arm and isheaded so as to be firmly clam d in the bracket arm. A link 30 isprovide with a sleeve 31 at the rear end thereof adapted to engage thestud 28. A sleeve 32 at the other end of the link 30 is ada ted toengage the stud 25. These two stu and 28 projecting as they do inopposite directions maintain their connection with the link without thelink being fastened thereto. As the feed rocker 10 oscillates it willthrou h the link cause the auxiliary feed bar 1 to slide back and forthin the sleeve bearings 19 and 20. Thus it is that the auxiliary feed dogis moved back and forth. As this auxiliary feed bar is mounted in bearincarried by the main feed bar, both feed ars will be raised and loweredby the eccentric 15.

The sleeve 23 is provided with a projecting arm 83 which extends througha slot 34 in the main feed bar. At the face of the main feed baropposite the auxiliary feed barare guide bars 35, 35 which are spacedfrom each other and are secured to the main feed bar b screws 36, 36.These bars are so placed that t e end 37 of the arm 33 makes a fairlyclose slidin contact with these guide bars. The ide are are ofsuflicient len b so that the ead 37 is in contact with t e guide barsthroughout the entire movementgiven to the auxiliary feed bar which isin excess of the movement givento the main feed bar. In other words, asthe feed rocker oscillates, the main feed bar will be iven a certainback and forth movement w ich is imparted to the main feed dog. Theauxiliary feed bar is moved by its separate and independent connectionto the feed rocker to a greater or less extent than the main feed bar.For fullin in the fabric in advance of the needle it wi 1 be given agreater stroke and for imparting a drag or stretching action to thefabric it will be given a less stroke. It may be iven the same stroke ifthe link is properly a justed on the bracket arm on the feed rocker.

From the above it will be noted that the auxiliary feed dog is attachedto the auxiliary feed bar at apolnt adjacent and very close to thesupporting sleeve 20 so that any wear between the sleeve and theauxiliary feed bar will have very little effect in changing the path ofthe movement of the auxiliary feed dog. The sleeve is attached to theauxiliary feed bar between the two supporting bearings therefor, andconsequently the auxlliary feed bar will be given its movement which isindependent of the movement imparted to the main feed bar in a positivemanner which imparts little or no lateral or side strains to theauxiliary feed bar. The auxilia feed bar ma be readily shifted in this seeve, both en wise and an ularly, for positioning the auxiliary feed(log relative to the needles, and to compensate for any inaccuracies inmanufacture, and insuring that the feed dog be set with its feed surfacehorizontal. The

arm projecting laterally from the sleeve and making contact with theguide bars at some distance from the auxiliary feed bar, holds said feedbar to a right line movement on the.

main feed bar and also prevents any lateral tilting of the auxiliaryfeed dog. Any wear between this arm and the guide bars will have littleor no effect on this right line movement of the auxiliary feed bar andthe plane of movement of the auxiliary feed dog.

It will be obvious that minor details in the manner of construction andthe arrangement of parts may be made without departing from the spiritof the invention as set forth in the appended claims. 4

Having thus fully described the invention, what is claimed as new isdesired to be secured by Letters Patent is:

1. A feeding mechanism for sewing machines comprising a main feed bar, amain feed dog carried thereby, a feed rocker to Ill which said main feedbar is connected, means for raising and lowering the feed bar, spacedbearing members carried by said main feed bar, asingle auxiliary feedbar mounted in said bearings, an auxiliary feed dog carried thereby,means connected to said auxiliary feed bar between said supportingbearings for imparting a differential feeding movement to said auxiliaryfeed dog and means for holding said auxiliary feed bar to a rightlinemovement on said main feed bar.

2. A feeding mechanism for sewing machines comprising a main feed bar, amain feed dog carried thereby, a feed rocker to which said main feed baris connected, means for raising and lowering the feed bar, spacedbearing members carried by said main feed bar, a single auxiliary feedbar mounted in said bearings, an auxiliary feed dog carried thereby, asleeve carried by said auxiliary feed bar and disposed intermediate saidsupporting bearings, a link connected to said sleeve and to the feedrocker for imparting a differential feeding movement to said feed barand means for holding said auxiliary feed bar to a right line movementon said main feed bar.

3. A feeding mechanism for sewing machines comprising a main feed bar, amain feed dog carried thereby, a feed rocker to which said main feed baris connected, means for raising and lowering the feed bar, spacedbearing members carried by said main feed bar, a single auxiliary feedbar mounted in said bearings, an auxiliary feed dog carried thereby,means connected to said auxiliary feed bar between said supportingbearings for imparting a diiferential feeding movement to said auxiliaryfeed dog, said auxiliary feed bar being circular in cross section andmeans independent of its supporting bearings for holding said auxiliaryfeed bar to a right line movement on said main feed bar.

4. A feeding mechanism for sewing machines comprising a main feed bar, amain feed dog carried thereby, a feed rocker to which said main feed baris connected, means for raising and lowering the feed bar, spacedbearing members carried by said main feed bar, an auxiliary feed barmounted in said bearings, an auxiliary feed dog carried thereby, asleeve carried by said auxiliary feed bar and disposed intermediate saidsupporting bearings, a link connected to said sleeve and to the feedrocker for imparting a differential feeding movement to said feed bar,an arm attached to said sleeve, guide bars between which the end of saidarm reciprocates for holding said auxiliary feed bar to a right linemovement on said main feed bar.

5. A feeding mechanism for sewing machines comprising a main feed bar, amain feed dog carried thereby, a feed rocker to which said main feed baris connected, means bearings, a sleeve attached to said auxiliary"- fcedbar intermediate said bearings, means attached to said sleeve forimparting a difi'erential feeding movement to said auxiliary feed bar,an auxiliary feed dog carried by said bar, and means for holding saidauxiliary feed bar to a right line movement in said bearings.

6. A feeding mechanism for sewing machines comprising a main feed bar, amain feed dog carried thereby, a feed rocker to which said main feed baris connected, means for raising and lowering the feed bar, spacedbearing members carried by said main feed bar, a hollow auxiliary feedbar circular in cross section having a sliding fit with said bearings, asleeve attached to said auxiliary feed bar intermediate said bearings,means attached to said sleeve for imparting a differential feedingmovement to said auxiliary feed bar, an auxiliary feed dog carried bysaid bar, means for holding said auxiliary feed bar to a right linemovement in said bearings, said sleeve being adjustably secured to saidauxiliary feed bar whereby said auxiliary feed bar may be shifted todifferent set positions.

7. A feeding mechanism for sewing machines comprising a main feed bar, amain feed dog carried thereby, a feed rocker to which said main feed baris connected, means for raising and lowering the feed bar, spacedbearing members carriedby said main feed bar, a hollow auxiliary feedbar circular in cross section having a sliding fit with said bearings, asleeve attached to said auxiliary feed bar intermediate said bearings,means attached to said sleeve for imparting a differential feedingmovement to said auxiliary feed bar, an auxiliary feed dog carried bysaid bar, means for holding said auxiliary feed bar to a right linemovement in said bearings, said last named means includin an armprojecting from said sleeve and guide bars between which the end of saidarm reciprocates.

8. A feeding mechanism for sewing ma chines comprising a main feed bar,a main feed dog carried thereby, a feed rocker to which said main feedbar is connected, means for raising and lowering the feed bar, spacedbearing members carried by said main feed bar, a hollow auxiliary feedbar circular in cross section having a sliding fit with said bearings, asleeve attached to said auxiliary 'feed bar intermediate said bearings,means attached to said sleeve for imparting a diiferential feedingmovement to said auxiliary feed bar, an auxiliary feed dog carried bysaid bar, means for holding said auxiliary feed bar to a right linemovement in said bearings, said last named means including an armprojecting from said sleeve, guide bars between which the end of saidarm reciprocates, said bars being disposed at a distance from saidauxiliary feed bar.

9. A feeding mechanism for sewing machines comprising a main feed bar, amain feed dog carried thereby, a feed rocker to which said main feed baris connected, means for raising and lowering the feed bar, spacedbearing members carried by said main feed bar, a single auxiliary feedbar mounted to slide freely in said bearings, an auxiliary feed dogattached to said feed bar and located adjacent one of said bearings,means attached to the said auxiliary feed bar intermediate said bearingsfor imparting a differential movement to the auxiliary feed dog andmeans for holding said auxiliary feed bar to a right line movement insaid supporting bearings.

10. A feeding mechanism for sewing machines comprising a main feed bar,a main feed dog carried thereby, a feed rocker to which said main feedbar is connected, means for raising and lowering the feed bar, spacedbearing members carried by said main feed bar, an auxiliary feed barmounted to slide freely in said hearings, an auxiliary feed dog attachedto said feed bar and located adjacent one of said bearings, meansattached to the aid auxiliary feed bar intermediate said bearings forimparting a differential movement to the auxiliary feed dog, means forholding said auxiliary feed bar to a right line movement in saidsupporting bearings, said last named means including an arm fixed tosaid auxiliary feed bar and projecting therefrom and guide bars betweenwhich the end of said arm reciprocates.

11. A feeding mechanism for sewing machines comprising a main feed bar,a feed dog carried thereby, a feed rocker to which said main teed bar isconnected, means for raising and lowering the feed bar, a support ingmeans carried by said main feed bar, a Single auxiliary feed bar mountedin said supporting means for endwise movement in dependent of the mainfeed bar, an auxiliary feed dog carried thereby, means connected to saidauxiliary feed bar for imparting a differential movement to saidauxiliary feed dog and [mains for holding said auxiliary feed bar to aright line movement on said main food bar.

12. A feeding mechanism for sewing machines comprising a main feed bar,a feed dog carried thereby, a feed rocker to which said main feed bar isconnected, means for raising and lowering the feed bar, a support ingmeans carried by said main food bar, a single auxiliary feed bar mountedin said supporting means for endwise movement independent of the mainfeed bar, an auxiliary feed dog carried thereby, a sleeve rigidly tures.

FREDERICK F. ZEIER. CLARENCE 0. SMITH.

